In domotic/inmotic environments, in driving or in playing sports, devices are known which function by means of switches or keypads or rather by means of remote control units, by cable or wirelessly (infrareds, radio frequency, bluetooth or voice-controlled technologies). However, in most cases, they must be manipulated using one's hands. This poses a major problem in situations in which users need their hands for the activity they are carrying out, such as, for example, driving, playing some sports (sailing, diving, skiing) or on security missions (military, police).
Other times, for example, in the voice-controlled systems, their usefulness is conditioned to certain environments in which there are not interferences due to background noise or rather when, for security-related reasons, it is not possible to use one's voice.
In addition to the above, the systems described hereinabove sometimes pose privacy-related problems in public environments in which users may be watched by third parties under conditions which do not ensure their privacy, for example at ATM machines or during the holding of meetings, events and ceremonies.
Lastly, people with physical disabilities which hinder or make it impossible for them to use their hands would benefit from a management device such as the one proposed, in the domotic and other realms.
To solve the problems described hereinabove, the use of physiological signals voluntarily modified by the users has been set out in theory. Thus, the field of Physiological Computing has researched the use of different physiological signals as possible inputs, for example, a personal computer, the most outstanding signals of which are the electrooculographic, electroencephalographic and electromyographic signals.
The electrooculogram (EOG) measures the differential in potential between the cornea and retina of the eye, a circumstance affording the possibility of recording the speed and direction of eye movement by means of electrodes placed on the skin in the vicinity of the eye. The electrode nearest to the cornea will record a positive potential, the one nearest the retina recording a negative potential. On moving one's eyes, the cornea and retina positions change in relation to the electrode, which gives rise to a change in potential. The EOG signal can be used by persons who have a high degree of disability, nevertheless, the EOG-based systems are comparatively expensive, requiring a great deal of attention and effort to control the proper cursor, and both calibrating and learning how to use them are complex.
The electroencephalogram (EEG) measures the brain's bioelectrical activity, and its use as an interface depends upon each user's ability to learn to control it. The physiological rhythms of the EEG in healthy adults when awake are alpha (8-13 Hz) and beta (above 13 Hz), although there may also be some theta (4.7 Hz) activities. These rhythms are of differing topographic distribution, are reactive to certain stimuli and are related to different states of alertness. With proper training, it is possible to generate EEG patterns which can be used, for example, to control the movements of a cursor or select letters or words on the computer screen. The main drawbacks of the EEG signal as an interface are their limitation in the band width and their spatial resolution, in addition to detection faults, contamination by electromyography and the effect of psychological variables. In general, the capacity to modulate the frequency of the brain's bioelectrical activity requires a great deal of training, for example, persons who have practice in meditating.
Electromyography (EMG) is based on measuring the bioelectrical activity associated with voluntary muscle contraction. One of the advantages of this signal is its relative immunity to the interferences coming from other physiological signals, in comparison to the EOG and EEG signals. The EMG signal can be used in different ways to manage a system, for example, in a way similar to a switch (ON/OFF system) but turning on/off a certain action with a voluntary muscle contraction. Another theoretical possibility would be the use of different estimated magnitudes of the EMG, which would make a proportional type of management possible. Lastly, it is feasible to define a pulse code in order to be able to perform different actions with one same muscle. This last strategy has been used, for example, in bioelectrical prosthesis control and is based on a 3-bit code (high-amplitude signal, low-amplitude signal and no contraction) without it being possible for a given code to start with “no contraction”, which makes a maximum of 18 commands possible. This system does not define a language based on the structure of the signal recorded.
In the state of the art, systems are currently known which employ this type of physiological signals as a computer input, one of which is a commercial product called Cyberlink-Brainfingers. This is a hardware (Cyberlink) and software (Brainfingers) system making it possible to control a computer (mouse/cursor, keyboard/keys) without using one's hands. It uses three types of neurophysiological signals: EEG, EOG and EMG. It is comprised of four elements: headband, with three plastic sensors for each one of the three signals, interface box (filter, amplifier, A/D converter) with USB port for connecting to the computer, cables and software which the user must install on the computer. The system picks up the three types of signals and distributes them among 11 information channels called brainfingers. Besides these 11 channels, Brainfingers combines the signals of the EEG and EMG channels into one single channel called BrainBody, which also serves to help users to modify their EEG activity by means of feedback from their EMG activity (on decreasing the degree of muscle contraction, users learn to relax and facilitate the start of the alpha rhythm). In users with limited facial mobility, the software can be formatted so that EOG or BrainBody will replace the EMG input.
In this system, the equivalent of a click of the mouse is a short contraction, the double click being two contractions. A sustained contraction (called “long click”) activates the cursor speed switch, which switches from “high speed and low resolution” to “low speed and high resolution” in order to be able to more easily click on icons or small targets on the computer screen. The system recognized up to four types of clicks depending on their duration (0.3, 0.6, 0.98 and 1.2 ms).
This system is explicitly for persons with a severe motor disability of neurological origins: cerebral palsy, amiotrophic lateral sclerosis, muscular dystrophy, multiple sclerosis, spinal cord injuries and patients with craneoencephalic trama sequelae.
Brainfingers has the following limitations:
1) Signal Type:
Brainfingers simultaneously uses the three neurophysiological signals described hereinabove. It gives the EMG channel a greater number of and more complex functions than the other two signals, which corresponds to the aforementioned EOG and EEG limitations as interfaces. Given that it is for users who have a major motor disability (EMG), it attempts to make up for this deficit with the user's EOG and EEG activity.
2) EMG Signal Characteristics                Muscle used: Brainfingers does not distinguish the action of an individual muscle, given that it picks up the EMG activity from the area beside the eyebrow, and therefore from both the frontalis and temporalis muscles.        Electrodes: Brainfingers places its electrode to pick up surface EMG on a fabric band around the forehead.        Parameters: Brainfingers uses only the SEMG signal duration parameter, and its code is limited to the mouse click, presented as a single click (of four different durations), double click and long click.        
3) User:
Brainfingers is specifically for people who have a severe motor disability of neurological origins who have residual motor activity of the frontalis or temporalis muscle.
4) Objective:
Brainfingers is designed specifically so that a user with a severe motor disability may communicate with a computer and with other people through the computer, as well as for providing moments of entertainment to someone who, under these conditions, is constantly lying in the same position by means of educational games, video games and musical composition.
5) Way of Use:
Brainfingers connects the user to the computer by means of cables and interacts with the user exclusively by way of the computer screen.
One of the objectives of the present invention is to control the environment using exclusively the EMG signal.
A further objective of the present invention is to make it possible to record the EMG signal from the skin surface or beneath the skin surface (i.e. from a piercing).
A further objective of the present invention is to use a specific muscle to facilitate the use of the system and enhance discreetness and ergonomics.
A further objective of the present invention is to make it possible to use several alternative muscles, enabling the users to choose the one which they find to be best and to rotate using one and another so as to avoid fatigue and overstrain.
A further objective of the present invention is for it to be possible for it to be used by persons who have enough motor control over any facial or cranial muscle and by any user with a motor disability.
A further objective of the present invention is to broaden the scope of application to make it possible for users to interrelate with their environment.
A further objective of the present invention is to broaden the scope of interaction by developing an alternative to the wired connection.
Yet a further objective of the present invention is the development of a language based on the parameters of duration, amplitude and interval of the EMG signal.